Wilberforce, William. 1759-1833. English campaigner vs slave trade.

Xian Incident. 1936. Chiang Kai-shek captured and forced to unite with Communists to fight Japanese.

Yorktown, Siege. 1781. British surrender to American and French forces. American Revolution.

Zelaya, José. 1853-1919. Nicaraguan president 1894-1909. Attempted to unify Central America by force and revolution 1909.

Zoroaster. Zarathustra. c628-551BC. Persian religious reformer, founder of Zoroastrianism. World is an eternal struggle between forces of good and evil.